Valve-gear mechanism for single-acting engines.



Patented Aug.'6, l90l. L. SEBPOLLET. VALVE GEAR MECHANISM FOR SINGLE ACTING ENGINES.

(Application filed. Mar. 27, 1900.)

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Patented Aug. 6, I901. L. SERPOLLET, VALVE GEAR MECHANISM FOR SINGLE ACTING ENGINES.

lAgplication filed Mar. 27, 1900.)

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No. 680,000. Patented Aug. 6, I90I. L. SERPOLLET. VALVE GEAR NIEcIIANIsNI FOR SINGLE ACTING ENGINES.

(Applicafion filed Mar. 27, 1900.)

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, and which has neither joints nor levers is char- UNITED. STATES PATENT OFFICE.

LEON SERPOLLET, or PARIS,- FRANCE.

VALVE-G EAR M EcHAN l sM i= R SINGLE-ACTING ENGINES.

SPEGIFIGATION forming part of Letters Patent N 6. 680,000, dated August 6, 1901.

Application filed March 27, 1900- To all whom it may concern:

Beit known that I, LEON SERPQLLET, of the city of Paris, in the Republic of France, have invented new and useful Improvements in Valve-Gear Mechanism for Single-Acting Engines, which improvements are fully set forth in the following specification.

The new steam distribution and exhaust mechanism for high-speed single-acting engines which is capable of exact adjustment acterized by a combination of a central cam having successive multiple actions of a generally known type with independent inlet and exhaust valves operating-mechanically under and against the pressure of the steam, assisted by the tension of springs, an essential sliding piece of variable length which carries the roller bearing against the cam and which may be adjusted in length so as exactly to take up the play, being inserted between the cam and the rod of each valve, in the prolongation of that rod.

In order that the following description may be understood, four sheets of drawings are an nexed hereto, of which- Figures 1, 2, and 3 show, respectively, first, a vertical half-section on the left hand along the axis of one of the cylinders and along the axis of an admission-valve and a half-elevation'; second, a horizontal half-section along the axis situated in a single plane and a half- 7 plan with the rods of the" four valves forming the right-hand group, an admission and an exhaust valve corresponding to each cylinder, and, third, a half end view on the right, showing the end of the cylinders and the valves and on the left a vertical half-section Fig. 4 is a plan showing the various admission and ex-- haust passages for the steam. Fig. 5 is an end view of the preceding figure. Figs. 6, 7, 8, 9, and show, respectively, sections on the lines I II III IV V of Fig. 4. Lastly, Figs. 11 and 12 show, respectively, a section of the cam-shaft through acam of special profile, causing to vary simultaneously with the duration of the admission the lead at the admission, and a development of this cam.

The device in question is hereinafter described, and the path of the steam from the inlet-orifice to the exhaust, indicated by dot- SerialNo. 10.357. (No modeLl ted lines hereinafter for admission and for exhaust) and by arrows, helps to make the description relatingto the figures understood.

Thestea'm arrives from the boiler at high pressure through the orificel, Figs. 1, 2, 4:, 5, and 8, and exhausts through the orifice 2 after having acted in the single-acting cylinder corresponding to the group of cylinders considered. On entering by the orifice 1 the steam passes into the valve-box 3, in which works the admission-valve 4, Fig. 1, which is held to its seat by the direct action of the steam and by the supplementary action of the spring 5 or 5, Figs. 1 and 2, and which can be opened more or less only under the action of the corresponding portion or incline of the central multiple action earn 7, acting by means of a roller 8 and a slide-rod 9 on the inclined rod 10 of the corresponding valve. As soon as one of the valves 4 is open the steam passes to the corresponding cylinder through one of the passages 11 or 12, Figs. 1, 4, 7, and 8, to return by other passages 13 and 14 of greater section, Figs. 1, l, 5, and 6, when the expansion of the steam in the cylinder has taken place and the piston after having accomplished its working stroke begins its return movement. The exhaust-passages to the cylinders being larger than the exhaust-passages thereof, back pressure is avoided. As soon as the piston reaches the end of its working stroke and is about to begin its return movement the cam-surfaces which open the exhaust-valves begin to act on the rods 15 15 for operating said exhaustvalves, Figs. 1, 2, and 3, and these latter valves rise, opening a passage for the exhaust-steam until the piston which drives back this steam has reached a certain point in the return stroke, after which the corresponding incline of thecam7 having passed against and in front of the roller 8 the corresponding exhaust valve 15 or 15 closes under the combined action of the steam and the spring 16 or 16, Figs-1, 2, and 3, and the steam inclosed in the portion of the cylinder remain ing to be traversed by the piston is compressed.

Between the rod of each valve and the common central cam, with its successive multiple action and inclines, are inserted the sliding while the otherend abuts agai'nst'ascrew' rods 9 9 17 17,of which one extremity, shaped like a fork,carries a roller 8 or 8' or 18 or 18,

with a head 19 or 19 or 20 or 20', which can 'be adjusted exactly in length and fixed by means of a lock-nut 21 or 21' or 22 or 22.

Between each screw-head 19 19 2O 20and the corresponding nut 21 or 21 or 22 or 22 is mounted a device forming an operating means for the. adjusting device, which may be the levers 23 23 and 24 24,against which the inclined rods 10 15 bear. In this way by means of this intermediate and distinct part all wear likely to arise can be taken 'up and perfect contact insured at all times between the cam and the-rollers and between the slid ing intermediate piece and thevalve-rods.

The distribution-cam 7, placed above thegear-case, its axis beingflocated in the-same vertical plane as the engine-shaft, has as many intermediate cylindrical surfaces or stopping-surfaces 25, 26, 27, and 28 (see Fig. 2) as there are rollers on the same side of the cam, and these rollers are opposite to these surfaces when the engine is stopped, placed thus between two inclines in opposite directions ending in cylindrical'surfaces with a boss corresponding to the maximum admission and exhaust. The cam 7, which has successive multiple actions controlling the admission 'and exhaust, is secured to a shaft 29, adapted to be moved in one direction or the other, either manually or by automaticallyoperated means, and alter simultaneously and equally the conditions of the admission andof the exhaust, as has been hereinbefore described. 7

On the end of the square shaft 29 there is mounted the toothed wheel 30,engaging with the wheel 31, of the same diameter, keyed to the engine-shaft 32. In order to vary the lead of admission or exhaust, gear-wheel 30, Fig. 3, may be moved to the left along shaft 29 out of engagement with gear-wheel 30 and gear 30 and its shaft carrying the actuatingcams turned backward or forward the distance'of one tooth, for example, and then again brought into engagement with gear 30, the position of which has not changed.

The toothed wheel 30 is mounted on the square shaft 29, which carries the central cam 7, and slides in this wheel on one hand and in a bush on the other side of the frame to admit of alterations in the admission. The adjustment is effected by causing the teeth of this wheel to enter into those of the wheel 31 at the desired position, as has been explained. This adjustment can therefore be efiected in every case to a tooth, and if the number of the teeth has been made prime with four (the number of the sides of the shaft) this adjustment may then be made to a quarter of a tooth.

The arrangement forming the subject-matter of Figs. 11. and 12 allows the lead at the admission to be varied at the same time as the duration of the admission by a special projection of the inclines of the cams.- Thus as the engine has to run at very dilferent speeds and has to give at thesame' time a very variable output it is necessary when it runs slowly at high pressure to diminish the lead, while when it has to produce little power when running at high speed and under reduced pressure as,for exam ple,on alevelit is economical to give lead. This increase in the lead at the moment when the admission is reduced and when the speed of the engine increases at the same time as its output is reduced is an indispensable'condition for the good working of a'high-speed engine. As may be clearly seen from Figs. 11 and 12, the

projection of the inclines of thecam as shown allows this increase of lead to be obtained automatically at the same time as the admission is reduced. The dead-point of the piston corresponds to the point 0.8 of the cam. In the development, Fig. 12, the incline corresponding to the beginning of the admission at a and the incline corresponding to the end of the admission b b show clearly that the lead comprised between the lines 0 a and a a varies at the same time as and in an inverse ratio to the duration of admission comprised between'the lines 0 a and b b.

By disposing the valve-rods 10, 10', 15, and 15 in an inclined position a more compact ar rangement is secured than in the case of the apparatus of my Patent No. 636,926, of N ovember let, 1899, (on which the present in= vention is an improvem ent,) wherein the valve-rods are horizontally disposed.

As most clearly shown in Fig. 3, the bottom of the chamber or gear-casing between the cylinders is made of thin sheet-iromwhich readily dissipates any heat acquired by the oil (in which the parts work) contained in the chamber.

From the drawings and the foregoing de-" scription it will be seen that the steam inlet and steam-exhaust passages are separated and removed from each other, so that the lower temperature of the exhaust-steam will not be imparted to or detrimentally influence the higher temperature of the ingoing steam.

1. In a steam-engine, the combination with a cylinder and its piston, of a steam admission or exhaust valve, a valve-rod for said valve movable in a longitudinal direction only, a rotatable cam and connections for driving the same, a sliding rod movable in a longitudinal direction only and actuated by said cam, and an adjustable connectionfor transmitting movement from the sliding rod to the valve-rod. I

2. In a steam-engine, the combination with a cylinder and its piston, of a, steam admission or exhaust valve, a valve rod for said valve movable in a longitudinal direction only, a rotatable, cam and connections for driving the same, a sliding rod movable in a longitudinal direction only and actuated by said cam, a lever pivoted at one end and at its other end adjustably connectedto the slid.- ing rod, said lever being adapted when moved to come into contact with and transmit movement to the valve-rod for opening the valve.

- located at the upper part of the gear-case and connections for driving the same, a sliding rod movable in a longitudinal direction only and actuated by said cam, and means for transmitting motion from the sliding rod to the valve-rod.

4;. In a steam-engine, a cylinder audits pis: ton, a steam-admission valve for the cylinder,- a valve-rod for said valve, a rotatable cam, means transmitting movement from the cam to the valve-rod, a shaft on which the cam is mounted, a gear-wheel on said shaft, a second gear-wheel rotated from a driven part of the engine and meshing with the first-mentioned gear-wheel to drive the cam-shaft, and means for changing the position of engagement of the two gear-wheels to vary the lead of steam admission.

5. In a multiplecylinder engine, two or more cylinders and pistons for the same, a gear-casing having a thin sheet-metal bottom interposed between the cylinders and adapted to contain a lubricant in which the piston conneotion's operate.

6. In a steam-engine, a cylinder, a steamadmission valve for the cylinder, and a camsurface of varying width for opening said valve the edge or side of said surface corresponding' to the beginning of steam admis I sion to the cylinder being inclined so that the lead of admission may be varied'by altering 1 the position of the cam-surface with relation to the valve and the edge or side of said camsurface corresponding to the termination of admission being at a greater inclination whereby the duration of admission decreases as the lead of admission increases.

7. In a steam-engine, a cylinder, a steam 1 admission valve for the cylinder,- and a rotatable cam-surface of varying width opening 5 said valve the edge or side of said surface corresponding to the beginning of steam adi mission to the cylinder being inclined so that 1 the lead of admission may be varied by alter LEON SERPOLLET.

Witnesses:

TOMINIQUE CASALONZA, ANTONIO FERNAND DE LA CALLE. 

